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Re: PMDD Dosage and Algae

On Fri, 24 Sep 1999, Beverly Wladyka wrote:

> We have an on-going problem with fuzzy green algae in our 180 gal and
> the battle to control it is beginning to wear me down - a lot,
> unfortunately.

Beverly, I can see a few problems and read between the lines to see a
couple more.

1) If you can shove all the plants from your 180 gallon tank into a 10
gallon tank and leave them there for weeks, then you really aren't growing
very many plants.  I couldn't cram all the plants from my 55 gallon tank
into a 10 gallon tank without crushing some down to green paste, and my 55
offers much less planting space than your 180.  Plant more plants to
create more competition for the algae.

2) You don't mention that your tank contains any algae eating fish.  You
really need to replace some of your existing fish with some algae eaters.
A tank with a moderate to heavy fish load, light planting, CO2 and
ferilizer in the water column is little more than an algae farm.  Algae
eaters like otocinclus or SAE's should thrive on your fuzzy greens.

3) In general nuisance green algae growth implies too many nutrients in
the water column.  In your case the nutrients are probably from fish
feeding and using two different water column fertilizers.  Low planting
density and additional fertilizer in the substrate means your rooted
plants aren't putting up much competition for the water column nutrients,
and the algae have a free ride.  Adding Jobe's spikes to your substrate is
probably a really bad idea right now.

4) If your water supplier says the water is low in phosphorus, I would
tend to believe them.  But if you do believe that phosphorus in your tap
water is a problem then the last thing you want to do is 40% daily water
changes.  That just provides the algae (and plants) a continuous supply of

5) Be PATIENT!  From your chronology of set-ups, problems, take-downs and
rebuilds it sounds like you've never given your tank much time to
stabilize.  This isn't particularly good for your fish and it makes it
impossible to judge the growth of your plants.  Also, while bubbling
plants provide instant gratification, it's a bad idea to use that as a
standard for good growing conditions.  With a moderate or heavy fish load
and lighting at 2 watts per gallon your plants can be very healthy and
grow very well without producing a bunch of bubbles, but you have to wait
longer to see that.

Aside from that, I am not a PMDD proponent and I can't coach anyone on
it's dosage.

Roger Miller